JP2006319139A - Superconducting apparatus and quenching protecting method of superconducting portion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a superconducting apparatus and a quenching protecting method of a superconducting portion capable of preventing a superconducting coil from being deteriorated and damaged following quenching and not requiring large capacity protective resistance. <P>SOLUTION: The superconducting apparatus comprises a power supply 10; the superconductor (superconducting coil 20) supplied with electric power from the power supply 10; a quenching detector 80 for detecting a precursory phenomenon of quenching of the superconducting coil 20; and power supply control means (power supply control circuit 90) for controlling the power supply 10 on the basis of a detection signal from the quenching detector 80, and adjusting a coil current such that the superconducting coil 20 does not get quenching. With this construction the superconducting coil 20 can be operated by controlling the power supply 10 without interrupting the superconducting coil 20 and the power supply 10, and keeping the current to such a coil current that the precursory phenomenon of the quenching is eliminated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a superconducting device and a quench protection method for a superconducting portion. In particular, the present invention relates to an apparatus and a protection method that can avoid burning due to quenching of a superconducting coil without using a large-capacity protective resistor.

The superconducting coil has zero electric resistance during operation, and can pass a large current to accumulate electric energy as magnetic energy. When a current I to the superconducting coils of the inductor box L, and the superconducting coil energy of L × I ^2/2 is accumulated.

  On the other hand, the superconducting coil may transition from the superconducting state to the normal conducting state due to external disturbance such as a wire movement. When the normal conducting state is locally generated in the superconducting coil, the temperature rises due to the Joule heat generation of the portion, the superconducting state in the vicinity is destroyed by the conduction heat, and quenching occurs where the superconducting state is suddenly destroyed. Since a large current flows through the superconducting coil and a large amount of energy is stored, if a quench occurs, the stored energy in the superconducting coil will be stored in the coil unless the energy stored in the coil is taken out of the coil quickly. It is consumed in the coil and causes deterioration and burnout of the coil.

  As a means for protecting the coil from such deterioration and burnout, a protection circuit shown in FIG. 2 is known (see Patent Document 1 for a similar technique). In this circuit, a superconducting coil 20 and a breaker 30 are connected in series to a DC power source 10, and a protective resistor 50 and a diode 60 are connected in parallel with the superconducting coil 20. In addition, a quench detector 80 is connected to the coil 20, and a signal from the detector 80 is configured to control the breaker 30 via a relay sequence 91 and a cutoff circuit 70. During normal operation of the coil 20, the breaker 30 is closed and a current flows through the superconducting coil 20. When a local normal conduction transition occurs in the coil 20, the quench detector 80 detects the quench precursor phenomenon, and opens the breaker 30 via the relay sequence 91 and the cutoff circuit 70 based on the detection signal. Accordingly, the current of the superconducting coil 20 flows through a closed circuit formed by the coil 20, the protective resistor 50, and the diode 60, and the stored energy is consumed by the protective resistor 50.

Japanese Laid-Open Patent Publication No. 7-19913

  However, in the conventional superconducting coil protection technology, if a local normal conduction transition of the coil is detected, the breaker is always cut off and the coil is quenched so that the coil does not burn by passing a current suddenly through the protective resistance. There were the following problems.

  When exciting or demagnetizing a superconducting coil of Inducts L, a voltage of L · (di / dt) is generated at both ends of the coil (di / dt is a time change rate of current). For example, when a current of I = 250 A flows through a coil of L = 40H having a large number of turns and a large inductance, the voltage generated in the coil becomes a high voltage of 10 kV or more. Therefore, there is a possibility that high voltage breakdown occurs in the superconducting coil.

  In a coil using a high-temperature superconducting wire having a critical temperature of 77K or higher, the propagation speed to the normal conducting state is usually slow, and the accumulated energy concentrates locally, resulting in a temperature rise, which tends to deteriorate the coil.

  Further, when the coil inductance L is large and the stored energy is large, the energy consumed by the protective resistor is also large, and it is necessary to use a large-capacity protective resistor. For example, when I = 250A and L = 40H, the energy consumed by the protective resistor is 1.2M joule, and a very large capacity protective resistor must be used.

  The present invention has been made in view of the above circumstances, and its main object is to provide a quench protection device and quench for a superconducting coil that can prevent deterioration and damage of the superconducting coil accompanying quenching and that does not require a large-capacity protective resistor. It is to provide a protection method.

  The superconducting device of the present invention includes a power source, a superconducting portion powered by the power source, a quench detector for detecting a precursor phenomenon of quenching of the superconducting portion, a power source based on a detection signal from the quench detector, and superconducting Power supply control means for adjusting the current of the superconducting part so that the part does not quench.

  In the apparatus of the present invention, the quench precursor phenomenon is detected by the quench detector, and the power source is controlled by the power source control means based on the detection result. Specifically, the current of the superconducting part is adjusted by controlling the power supply without interrupting the superconducting part and the power supply. Thereby, it is possible to operate the superconducting part while maintaining the current of the superconducting part so that the precursor phenomenon of quenching is eliminated. Therefore, basically, it is not necessary to cut off the power source and the superconducting part, and it is not necessary to provide a breaker or a protective resistor.

  A superconducting coil is a typical example of the superconducting part, but a superconducting cable is also included.

  The power control means controls the current setting means for setting the current of the superconducting part, the sweep adjusting means for sweeping the current of the superconducting part, and the current setting means and the sweep adjusting means based on the detection signal from the quench detector. And what has the relay sequence which adjusts so that a superconducting part may not quench the electric current from a power supply is suitable.

  By using the power supply control means having this configuration, it is possible to operate the superconducting part while controlling the power supply to sweep the current of the superconducting part and maintaining the current of the superconducting part so that the superconducting part does not quench.

  In the device of the present invention described above, a breaker that cuts off the power source and the superconducting part, and a protective resistor that consumes the accumulated energy of the superconducting part when the power source and the superconducting part are cut off by the breaker may be provided.

  With this configuration, when the adjustment of the current of the superconducting part by the power supply control means is uncontrollable, the breaker is dropped to commutate the current of the superconducting part to the protective resistor, and the stored energy is consumed to avoid burning the superconducting part. Can do.

  In addition, the quench protection method of the superconducting part of the present invention detects the quenching phenomenon of the superconducting part, and when the quenching precursory phenomenon is detected, controls the power supply that supplies power to the superconducting part and quenches the superconducting part. It is characterized in that the current of the superconducting part is adjusted so as not to reach.

  In the quench protection method for a superconducting portion of the present invention, a quench precursor phenomenon is detected, and the power source is controlled based on the detection result. Specifically, the current of the superconducting part is adjusted by controlling the power supply without interrupting the superconducting part and the power supply. Thereby, it is possible to operate the superconducting part while maintaining the current of the superconducting part so that the precursor phenomenon of quenching is eliminated. Therefore, basically, it is not necessary to cut off the power source and the superconducting part, and it is not necessary to provide a breaker or a protective resistor. In order to adjust the current of the superconducting part by controlling the power supply, for example, the current of the superconducting part may be selected such that the current of the superconducting part is swept within a predetermined range to eliminate the quenching phenomenon.

  In the method of the present invention described above, a breaker that cuts off the power source and the superconducting part, and a protective resistor that consumes the accumulated energy of the superconducting part when the power source and the superconducting part are cut off by the breaker may be provided. With this configuration, when adjustment of the current of the superconducting part by power supply control is uncontrollable, it is possible to avoid burning of the superconducting part by dropping the breaker and commutating the current of the superconducting part to the protective resistance and consuming the stored energy it can.

  According to the apparatus and method of the present invention, the current of the superconducting part is adjusted by controlling the power supply without interrupting the superconducting part and the power supply. Thereby, it is possible to operate the superconducting part while maintaining the current of the superconducting part so that the precursor phenomenon of quenching is eliminated. Therefore, basically, it is not necessary to cut off the power source and the superconducting part, and it is not necessary to provide a breaker or a protective resistor.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a circuit diagram of the device of the present invention.

  The apparatus according to the present invention includes a DC power source 10, a superconducting coil 20 (superconducting portion) excited by power supply from the power source 10, a quench prevention circuit 100 and a cutoff circuit 70 for preventing quenching of the superconducting coil 20. . The DC power supply 10 is connected in series to the superconducting coil 20 via the breaker 30 and the output terminal 40. The superconducting coil 20 is formed by winding a Bi2223 series superconducting wire around a core material, and is cooled using liquid nitrogen as a refrigerant. Further, a protective resistor 50 and a diode 60 are connected to the superconducting coil 20 in parallel. The protective resistor 50 is used to consume energy stored in the superconducting coil 20 when it is difficult to suppress quenching by appropriately adjusting the coil current of the superconducting coil 20 by the quench prevention circuit 100 described later. The diode 60 regulates the direction of the current flowing from the superconducting coil 20 to the protective resistor 50.

  On the other hand, the quench prevention circuit 100 includes a quench detector 80 that detects a quench from a voltage rise state at the time when a quench precursor phenomenon occurs while the superconducting coil 20 is energized, and a coil that eliminates the quench precursor phenomenon. And a power supply control circuit 90 for adjusting the current. The quench detector 80 includes a variable resistor 81, an amplifier 82, a detection voltage setting comparator 83, and a detection time setting counter 84. The middle point of the coil 20 is taken with a voltage tap, and a balance signal is taken with the voltage tap of the variable resistor 81 connected in parallel with the coil 20 and detecting the voltage of the superconducting coil 20. When a quench precursor phenomenon occurs in the superconducting coil 20 and the resistance value of the coil 20 increases, the bridge circuit composed of the variable resistor 81 and the superconducting coil 20 is unbalanced, and the resulting differential voltage is output as a signal. . This voltage signal is amplified by the amplifier 82 and input to the detection voltage setting comparator 83. At that time, a time limit is set by the detection time setting counter 84, and if a voltage signal that rises at a certain slope or more is output during that time limit, it is regarded as a precursor phenomenon of quenching, and the power supply control circuit 90 turns on the power. Control and adjust coil current.

  The power supply control circuit 90 includes a relay sequence 91, a current setting switch 92, a sweep adjustment switch 93, a D / A converter 94, and an integrator 95. When the comparator 83 outputs a voltage signal that rises with a certain slope, the relay sequence 91 commands the current setting switch 92 and the sweep adjustment switch 93 to operate. By this operation command, the current setting switch 92 defines the range of the coil current set via the D / A converter 94, and within the coil current range, the sweep adjustment switch 93 sets the power supply 10 via the integrator 95. To control. That is, the current of the power supply 10 is swept, and the coil current is lowered so that the bridge circuit formed by the variable resistor 81 and the superconducting coil 20 is balanced and the quench precursor phenomenon is eliminated. The operation of the superconducting coil 20 is continued while holding the coil 20 at a coil current that does not quench.

  According to the above apparatus, the superconducting coil 20 and the power source 10 are not cut off, the power source 10 is controlled to adjust the coil current, and the coil current is maintained so as to eliminate the quenching precursor phenomenon. Can drive. Therefore, it is basically unnecessary to use a breaker or a protective resistor.

  However, when trouble occurs in the quench prevention circuit 100 and adjustment of the coil current is not normally performed, it is preferable to use the interruption circuit 70. The interruption circuit 70 forcibly creates a zero point of current in the breaker to safely cut off the direct current. That is, when the adjustment of the coil current is not normally performed, it is preferable that the breaker 30 is dropped via the cutoff circuit 70 by a command from the relay sequence 91 so that the DC power supply 10 and the superconducting coil 20 can be cut off. . Thereby, the stored energy of the superconducting coil 20 is consumed by flowing through the protective resistor 50 in the direction regulated by the diode 60 as a current. When the adjustment of the coil current is not normally performed, for example, the generation of the differential voltage between the variable resistor 81 and the superconducting coil 20 may not be eliminated within a predetermined time set by the detection time setting counter 84.

  The device of the present invention and the method of the present invention can be effectively used as a technique for preventing quenching of a superconducting part such as a superconducting coil.

It is a circuit diagram of the superconducting device of the present invention. It is a circuit diagram of the conventional superconducting device.

Explanation of symbols

10 DC power supply 20 Superconducting coil 30 Breaker 40 Output terminal 50 Protection resistance
60 Diode 70 Cutoff circuit 80 Quench detector 81 Variable resistance 82 Amplifier
83 Detection voltage setting comparator 84 Detection time setting counter 90 Power control circuit
91 Relay sequence 92 Current setting switch 93 Sweep adjustment switch
94 D / A converter 95 Integrator 100 Quench prevention circuit

Claims (3)

Power supply,
A superconducting part powered from a power source;
A quench detector for detecting a precursor phenomenon of the quench of the superconducting part;
A superconducting device comprising: a power source control unit that controls a power source based on a detection signal from a quench detector and adjusts a current of the superconducting unit so that the superconducting unit does not quench. Power control means
Current setting means for setting the current of the superconducting part;
Sweep adjusting means for controlling the current sweep of the superconducting portion;
2. A relay sequence for controlling the current setting means and the sweep adjustment means based on a detection signal from the quench detector to adjust the current of the superconducting part so that the superconducting part does not quench. The superconducting device described in 1. Detecting the precursor phenomenon of quenching in the superconducting part,
A quench protection method for a superconducting part, characterized in that when a quench precursor phenomenon is detected, the power supply for supplying power to the superconducting part is controlled to adjust the current of the superconducting part so that the superconducting part does not quench. .

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